Fine tuning device for stringed instruments



March 17, 1959 lNFELD 2,877,678

FINE TUNING DEVICE FOR STRINGED INSTRUMENTS Filed April 16, 1957 United States Patent FINE TUNING DEVICE FOR STRINGED INSTRUMENTS Otto Infeld, Vienna, Austria Application April 16, 1957, Serial No. 653,157 Claims priority, application Austria June 1, 1956 4 Claims. (Cl. 84302) A fine tuning device for stringed instruments is known, which consists of a string holder, in which the tensioning levers for tuning the individual strings are pivotally supported and the adjusting screws for adjusting the tensioning levers are inserted. The tensioning levers have two arms, one of which is upwardly bent in the shape of a hook and serves to receive the fixing button of the string, whereas the other arm extends along the underside of the string holder approximately parallel thereto and forces the adjusting screw against the same. To tension the string that arm is moved downwardly towards the sound board of the instrument. In stringed instruments having a low bridge such as guitars and mandolins, the space below the string holder is too small to permit the use of such adjusting devices.

It is also known to insert the adjusting screws in the string holders by affixing a screw having a threaded axial bore in the hole which serves in a usual string holder for receiving the fixing button or a fixing loop of the string, and screwing the adjusting screw in said threaded bore. In this case the tensioning lever arranged with an upwardly directed hook-shaped end is pivoted to a supporting plate rather than on the string holder itself. Thus, this known device may be afiixed as a unit individually for each string to a normal string holder. It has the disadvantage, however, that the space below the string holder is required for the pivotal movement of the tensioning lever in an extent even larger than in the known fine tuning device mentioned in the first place hereinbefore, because the supporting plate is also afiixed to the underside of the string holder so that the pivot of the tensioning lever is even lower than when carried by the string holder itself.

It is also known to arrange the supporting plate for the tensioning levers on the upper side of the holder and to hold it fast with the aid of a threaded bolt which extends through the hole in the string holder and has also a female thread, in which the adjusting screw is screwed. The hook-shaped end of the tensioning lever is upwardly directed and its other end extends into the slot which opens into the hole in the string holder and through another slot formed in the threaded bolt to below the adjusting screw. In this construction, therefore, the string engages the hook-shaped end of the tensioning lever above the string holder and when being tensioned urges the entire string holder with the fixing device downwardly against the sound board, e. g., of a guitar, so that this known fine adjusting tuning device appears also unsuitable for stringed instruments having a low bridge.

It is an object of the invention to provide a fine tuning device which is particularly suitable for stringed instruments having a low bridge, such as guitars and mandolins, but is advantageous also for violins and the like instruments having a higher bridge. The invention resides essentially in that the hook-shaped arm of the tensioning lever extends downwardly towards the sound board of the instrument below the supporting plate or string holder and the adjusting screw is screwed in the longer second arm and bears on the support for the tensioning levers or on the string holder so that the pivotal movement of the longer arm of the straining lever takes place above the string holder and the string holder is prevented from being depressed against the sound board during the tensioning of the string because the latter is afiixed to the lever at a point disposed below the string holder. Thus the space between the string holder and the sound board is no longer occupied by the fine tuning device and is not or not substantially reduced during the tensioning of the wire, dilierent from the known constructions mentioned hereinbefore, so that the tuning device can also be used in instruments having a low bridge and an engagement of the tensioning levers with the sound board in high-bridge instruments, as may be the case in the known construction for individual strings, is avoided.

The fine tuning device'according to the invention may be designed for use with individual strings or several fine tuning devices may be juxtaposed to form a separate fine tuning string holder. These two embodiments are shown by way of example in the accompanying drawing.

Fig. 1 is a longitudinal sectional view of a fine tuning device for an individual string.

Fig. 2 is a top plan view of the device shown in Fig. 1.

Fig. 3 is a longitudinal sectional view of a string holder combined with a fine tuning device for several strings.

Fig. 4 is a top plan view of the device shown in Fig. 3.

Fig. 1 shows a fine tuning device which is affixed to the string holder 1 for a string 10 and comprises a supporting plate 2, secured to the top face of the string holder 1 by a screw 3, which extends through hole 4 formed in the holder for receiving the fixing button 10 or the fixing loop of the string 10.

The two-armed tensioning lever 5 is pivoted by means of the pin 6 at the free end of the plate 2. The arm 7 of the lever 5 has the shape of a downwardly bent hook and serves to receive the button 10' or an equivalent thereof, such as the fixing loop of the string 10, underneath the plate 2, as is shown in Fig. 1. The longer second arm 8 of the lever 5 extends above the string holder 1 and carries at its end the adjusting screw 9, which bears on the plate 2 afiixed to the string holder 1. To tension the string 10 the screw 9 is turned in the clockwise sense whereby the arm 8 is swung upwardly and the book 7 is swung in the rearward direction.

According to Figs. 3 and 4 the plate 16 is aifixed by means of the stirrup member 15, forming the string holder, to the rim 14 of the instrument. The plate 16 is inwardly turned at one end for receiving the shaft 17 common to the tensioning levers 18 whereas its other end is reversely bent around the stirrup member 15. The adjusting screws 19 bear on that reversely bent end 16 of the plate and are screwed into the end portions of the longer lever arms 20 of the levers 18. In the vertical cross-section of Figure 3, the lever 20 is shown mounted for vertical motion within slots 22 relative to the plate 16. The slots are shown in Figure 4 as having a front portion adjacent to the shaft 17 narrowed sufliciently to prevent lateral motions of the lever. The slots are enlarged, however, towards the rear of the plate 16 to a width greater than that of the levers in order to provide sidewise clearance, 23, for the end portions of the levers. The hook-shaped shorter lever arm 21 extends downwardly and serves to receive the fixing button 10 or the fixing loop of the string. When it is desired to tension the string the screw 19 is turned in the tightening sense, whereby the lever arm 20 is swung upwardly.

I claim:

1. A fine tuning device for stringed instruments, which comprises a support consisting of a sheet metal plate turned inwardly at mutually opposite ends, a shaft mounted in one of said inwardly turned ends, a plurality of double-armed tensioning levers pivotally mounted on said shaft, each of said levers having a hook-shaped arm extending below said support and adapted to have one end of a string affixed thereto, and a second arm longer than said hook-shaped arm, said device comprising further a plurality of adjusting screws each of which is screwed in the second arm of one of said levers and bears on the other of said inwardly turned ends of said plate, and a stirrup-shaped holding member inserted in said other inwardly turned end of said plate and adapted to be affixed to an instrument body.

2. A musical string-tuning device for a stringed instrument comprising in combination therewith: a string holder; a supporting plate; means operatively connecting said supporting plate to said string holder; at least one tensioning lever, having an elongated arm extending rearwardly over said supporting plate, and a short arm bent angularly downwards from one end of said elongated arm; means pivoting said two arms to said supporting plate at the point of intersection of said two arms; a threaded adjusting screw threadedly engaged in the opposite end of said elongated arm, said adjusting screw bearing against said supporting plate; said short arm including a hook-like portion extending downwardly underneath said supporting plate and terminating rearwardly of said pivot; said hook-like portion including a stringholding means; said adjusting screw being operable to pivot said lever about said pivot means, to move said short arm and said string-holding means rearwardly and said elongated arm upwardly away from said supporting plate.

3. A musical string tuning device as claimed in claim 2, wherein said supporting plate is fixed above said string holder.

4. A musical string tuning device as claimed in claim 2, comprising a plurality of tensioning levers; a shaft common to all of said levers at the free end of said supporting plate; each said lever being equidistantly spaced and pivoted on said shaft; said supporting plate being formed with slots therein, one of said slots for each said lever, each said slot providing clearance for reciprocal vertical pivoting movements of one of said levers, wherein the fixed end of said supporting plate is turned inwardly underneath the said adjusting screws of said levers, to provide a bearing platform for them.

1 References Cited in the file of this patent UNITED STATES PATENTS 1,657,890 Mertes Jan. 31,1928 2,585,661 Kluson Feb. 12, 1952 FOREIGN PATENTS 251,856 Italy Feb. 5, 1927 

